1. Field of the Invention
The present invention relates to adhesives for electronic parts and adhesive tapes using them, which are suitable for use in production of tape carrier packages (TCP), tape BGA (ball grid arrays), CSP (chip size packages), etc. which are suitable for the inclusion of many pins, miniaturization and high density assembly in a fabrication process of semiconductor devices, and particularly are most suitable for use in bonding of semiconductor chips, radiation plates and circuit boards making good used of TAB (tape automated bonding) techniques, which are all used in these packages.
2. Description of the Related Art
In the conventional adhesive tapes for electronic parts, an adhesive layer composed of an aliphatic polyamide resin and an epoxy resin, a polyamide resin, an epoxy resin and a phenol resin, or the like is formed on at least one side of a heat-resistant film as represented by TAB tapes. As the polyamide resin in the adhesive layer, is used nylon, dimeric acid polyamide or the like.
Film carrier tapes represented by the TAB system have been recently required to make fine by narrowing their conductor width and conductor spacing. Therefore, such a conventional adhesive as described above has become insufficient in insulating property and heat resistance. In wire bonding, copper forming a circuit requires to be plated with nickel or gold. Electro-plating has heretofore been used. However, electroless plating is suitable for thin film plating attendant upon the fining. By the way, the above-described adhesives heretofore used in TAB tapes have encountered problems such as lowering of electrical reliability due to lowering of their adhesive strength by a high temperature upon electroless plating and wire bonding failure by adsorption of impurity components such as sulfur in a plating solution.
In recent years, circuit board materials of the additive type, in which a copper layer is formed directly on a polyimide film or the like, have begun to be marketed. Since perforating in the fabrication of a semiconductor device comes to depend on laser and etching, however, they have a demerit that the productivity of semiconductor devices is low. The additive type circuit board material itself also involves a problem of poor productivity, since plating forms its conductor layer.
With such circumstances in view, various kinds of polyimide adhesives have been developed to date. For example, Japanese Patent Application Laid-Open No. 25453/1993 discloses a heat-resistant resin adhesive comprising soluble polyimide siloxanes consisting of an aromatic tetracarboxylic acid component composed mainly of a biphenyltetracarboxylic acid, a diaminopolysiloxane component and an aromatic diamine component, an epoxy compound and an epoxy hardener, and Japanese Patent Application Laid-Open No. 25452/1993 discloses a heat-resistant adhesive in which a bismaleimide resin is additionally added to the above described adhesive. Furthermore, Japanese Patent Application Laid-Open No. 200216/1994 discloses an adhesive film comprising a polyimide resin having silicon units, and an epoxy resin, and describes the polyimide resin to the effect that at least 1 mol % of a divalent aromatic group having a functional group is preferably contained as a component thereof.